This invention relates to a magnetic tape cartridge, and more particularly to a magnetic tape cartridge comprising a cartridge casing and a single reel which is housed in the cartridge casing for rotation and around which a magnetic tape is wound.
As a recording medium for use in an external memory of a computer or the like, there has been known a magnetic tape cartridge comprising a magnetic tape wound around a single reel and a cartridge casing in which the reel is housed for rotation. Since the magnetic tape is used for storing data in a computer or the like and important information is stored on the magnetic tape, the magnetic tape cartridge is structured so that trouble such as tape jam does not occur and the magnetic tape is not accidentally drawn out.
There has been known a magnetic tape cartridge provided with a memory element other than the magnetic tape so that the contents of the information recorded on the magnetic tape, the kind of the magnetic tape and the like can be detected from the memory element without reading out the information from the magnetic tape. The memory element generally comprises a semiconductor chip on which the contents or the like of the information recorded on the magnetic tape are recorded by a non-contact system such as an electromagnetic induction system and the information recorded on which is read out by a non-contact system such as an electromagnetic induction system.
It is necessary that the memory element is disposed in a position on the surface of the magnetic tape cartridge or inside the magnetic tape cartridge where the memory element does not interfere with the reel. Further, it is necessary that the memory element is disposed in a position where information read-out systems can have access to the memory element so that the information stored therein can be easily read out by an external memory means, a magnetic tape cartridge take out means which takes out a selected magnetic tape cartridge in a library where a plurality of magnetic tape cartridges are stored, or the like.
The cartridge casing is formed by fastening together rectangular upper and lower casing halves at their four corners by metal screws. When the metal screws are of iron, read and write of information from and on the memory element can be adversely affected.
In view of the foregoing observations and description, the primary object of the present invention is to provide a magnetic tape cartridge in which the memory element is disposed in a position where information read-out systems can easily gain access to the memory element.
Another object of the present invention is to provide a magnetic tape cartridge in which the upper and lower casing halves are fastened together by a fastening structure which cannot adversely affect read and write of information from and on the memory element.
In accordance with a first aspect of the present invention, there is provided a magnetic tape cartridge comprising a magnetic tape wound around a single reel and a substantially rectangular cartridge casing which is formed by fastening upper and lower casing halves by a fastener means and in which the reel is housed for rotation, wherein the improvement comprises that
a non-contact memory element is provided in at least one of the four corner portions of the lower casing half.
In the case where a tape draw-out opening is provided in a corner of the cartridge casing, a non-contact memory element is provided in at least one of the other three corner portions.
The non-contact memory element is a memory element on which information can be recorded by a non-contact system such as an electromagnetic induction system and information recorded on which can be read out by a non-contact system such as an electromagnetic induction system. It is preferred that the memory element be square in shape from the viewpoint of mounting facility.
It is preferred that the memory element be held at about 45xc2x0 to the bottom surface of the cartridge casing. So long as the memory element is held at about 45xc2x0 to the bottom surface of the cartridge casing, the memory element may be held by any holding means. For example, the memory element holding means may comprise a recess which is formed in the lower casing to receive a lower edge of the memory element and a recess which is formed in the upper casing to receive an upper edge of the memory element, or may comprise a holding portion which is formed in the lower casing half to be engaged with a lower portion of the side edges of the memory element and a holding portion which is formed in the upper casing half to hold an upper portion of the side edges of the memory element. Ribs for reinforcing the upper and lower casing halves may be used to hold the memory element.
The expression xe2x80x9cthe memory element is held at about 45xc2x0 C. to the bottom surface of the cartridge casingxe2x80x9d means that the memory element need not be held strictly at 45xc2x0 C. to the bottom surface of the cartridge casing so long as the memory element is held to the bottom surface of the cartridge casing at an angle at which information stored in the memory element can be read by a non-contact system in both a recording and reproducing apparatus and a library as will be described in more detail later.
A tape draw-out opening through the magnetic tape in the cartridge casing is drawn out is generally formed in a side wall at one of two front corners (leading corners as seen in the direction of insertion of the magnetic tape cartridge into a recording and reproducing apparatus). The expression xe2x80x9cin the case where a tape draw-out opening is provided in a corner of the cartridge casing, a non-contact memory element is provided in at least one of the other three corner portionsxe2x80x9d means that the non-contact memory element is provided in at least one of the other of the front corner portions and the two rear corner portions. For example, one non-contact memory element may be provided in each of one front corner portion and one rear corner portion. The xe2x80x9ccorner portionxe2x80x9d means a space formed between the corner of the lower casing half of the cartridge casing, formed by a pair of side walls normal to each other, and the outer peripheral surface of the reel.
It is preferred that the upper and lower casing halves be formed of a non-magnetic material and the fastener means near the non-contact memory element be formed of a non-magnetic material. For example, the fastener means near the non-contact memory element may comprise a screw formed of a hard plastic material and a boss which is formed on the upper or lower casing half and in which a sleeve of a soft plastic material is fitted so that a front end portion of the screw is screwed into the sleeve in a self-tapping fashion. In this case, it is preferred that the outer surface of the sleeve and the inner surface of the boss facing each other at the interface therebetween be serrated.
Further, the fastener means near the non-contact memory element may comprise bosses which are formed respectively on the top wall of the upper casing half to extend downward and on the bottom wall of the lower casing half to extend upward and are bonded together at their ends by adhesive or welding.
Further, the fastener means near the non-contact memory element may double as the memory element holding means in the lower casing half. In this case, the fastener means may comprise a pair of resilient engagement pieces which are formed on the inner side of the side wall of the upper casing half to extend inward downward laterally spaced from each other and are adapted to be engaged with the inner side of the side wall of the lower casing half, and the memory element is held by the resilient engagement pieces.
When the magnetic tape cartridge is loaded in the recording and reproducing apparatus, the magnetic tape cartridge is generally held at a level lower than the level at which the magnetic tape cartridge is inserted into the apparatus. When the non-contact memory element is disposed in the upper casing half, the distance between the memory element and the information read/write means of the recording and reproducing apparatus becomes large, which is disadvantageous in view of stably effecting read and write of information. In accordance with the present invention, since the memory element is disposed in the lower casing half, the distance between the memory element and the information read/write means of the recording and reproducing apparatus becomes small and read and write of information can be stably effected.
When the memory element is disposed in one of the rear corner portions, information recorded on the memory element can be read from behind, and accordingly, the magnetic tape cartridge can be stored in a library in the same position as the position in which the magnetic tape cartridge is loaded in a recording and reproducing apparatus.
When the memory element is held at about 45xc2x0 C. to the bottom surface of the cartridge casing, the information read/write means can face the surface of the memory element at 45xc2x0 C. both from below and from front and the information read/write means may be positioned either below the magnetic tape cartridge or in front of the same, whereby the degree of freedom in disposing the information read/write means is increased, which results in a higher degree of freedom in designing the recording and reproducing apparatus.
The cartridge casing is formed by fastening together rectangular upper and lower casing halves at their four corners by screws. When the metal screws are of iron, read and write of information from and on the memory element can be adversely affected by the magnetic material disposed near the memory element. In accordance with the present invention, by forming the fastener means near the memory means of a non-magnetic material, the aforesaid problem can be easily overcome.